Selective electrical signaling.



L. M. POTTS.

SELECTIVEELECTRICAL SIGNALING.

APPLICATION FILED MAY7,1910- RENEWED FEB. 19.1915.

w 1 9 111$ Um Patented Apr. 113, 1915.

5 SHEETS-SHEET 1.

4 x E L Y; A j A A T; j Q) I n L. M. POTTS. SELECTIVE ELECTRICAL SIGNALING. APPLICATION FILED MAY7, 1910. RENEWED FEB. 19.1915.-

Patentetl Apr. 13, 1915.

6 SHEETS-SHEET 2.

L. M. POTTS.

SELECTIVE ELECTRICAL SIGNALING.

APPLICATION I-ILED MAY7. 1910. RENEWED F B. 19,1915.

1 135 wmw Patented. Apr 13,1915.

- I 04 aw? A170 ME MI. A?

L. M. POTTS.

SELECTIVE ELECTRICAL SIGNALING.

APPLICATION FILED MAY7,1910. RENEWED FEB. 19.1915.

' lPatentd Apn13, 1915.

5 SHEETS-SHEET 4.

L. M. POTTS.

SELECTIVE ELECTRICAL SIGNALING.

APPLICATION FILED MAYT, 1910. RENEWED FEB. 19.1915.

5 SHEETS-SHEET 5.

Patented. Apr. 13, 1915.

|N\ I II II II 1 I PHI I I l ma I l linl hl I U III II|I III IIIII IK -IHI W I IU IH I I I I I IIIIU I I II WIII I IWIAHMHMN j l IIIIY men,

LOUIS MAXWELL FOT'IS, 0F BALTIMORE, MARYLAND, ASSIGNOR, BY MESNE ASSIGN- MENTS, TO AUSTIN McLANAHAN, 0F BALTIMORE, MARYLAND.

SELECTIVE ELECTRICAL SIGNALING.

Specification of Letters Patent.

Patented Ap1u'I3, 1915.

Application filed May 7, 1910, Serial No. 559,968. Renewed February 19, 1915. Serial No. 9,416.

To all whom it may concern:

Be it known that I, Louis MAXWELL Porrs, a citizen of the United States, residing at Baltimore, State of Maryland, have invented certain new and useful Improvements in Selective Electrical Signaling, of which the following is a specification.

This invention relates to selective electrical signaling which, broadly considered, includes the operation of electric telegraphs, telephones or any other apparatus where it is desired to effect a series of mechanical operations by electricalsignals sent over a line, and the primary object of-the said invention isto provide a system of this character which shall be positive and accurate in action and at the same time comparatively simple.

In order that my said invention may be more fully understood, I shall now describe in detail, With reference to the accompanying drawings, one specific embodiment thereof, and later point out what I claim.

In the accompanying drawings, Figure 1, is a diagram of an arrangement of receiving circuits and apparatus embodying my invention; Fig. 2, a side elevation'of a special form of slow acting relay forming part of said receiving apparatus; Fig.3, a front elevation of said relay; Fig. 4, an enlarged detail vertical central section of the dash pot mechanism of said relay; plan viewof one of the double tongued relays shown in Fig. 1; Fig. 6, a skeleton per spective view of a form of transmitting apparatus which may be used as a part of my present system of selective signaling; Fig. 7, a fragmentary detail front elevation showing slotted block and ends of cam levers held by the said block against the side thrust, all parts of the transmitting apparatus of Fig. 6; Fig. 8, a top plan view of the lever operating line impulse cams of Fig. 6;

Fig. 9, a top planview of the key looking cam of Fig. 6; Fig. 10, an end elevation looking down on top of the clutch mechanism of Fig. 6; Fig. 11, an enlarged detail side elevation partly in section of the clutch and cam mechanism of Fig. 6; Fig. 11*, a section on line 11 -11 Fig. 11; Figs. 12 and 13, are semi-diagrammatic elevations showing two positions in the operation of the clutch release mechanism; Figs. 14: and 15, two enlarged perspective views of the clutch Fig. 5, a top pawls; Fig. 16, a side elevation partly in section of a portion of the key locking mechanism; Fig. 17, a diagram of signal combinations; Fig. 18,- a diagram showing the arrangement of lugs on a plurality of actuating bars herein described, and Fig. 19, a diagram of the signaling current.

In thefollowing description I shall take up'first the reception of the signals, and, for this purpose reference will first be had particularly to Fig. 1 of the drawings. In the specific form of my invention shown in this figure, I employ a single main line wire 1 which leads from a source of current at a sending station to the receivin station of Fig. 1 where it is grounded. %)bviously a metallic return may be used instead of the ground. The circuit of this main line at the receiving station traverses the coils "of a polar relay 2, provided with two tongues 3 and 4 which are movable between contacts 5- 6 and .7-8 respectively. These contacts are cross-connected to a local source of direct current through resistances 9 and 10, as shown.

Connected in series with the tongue 3 of ,line relay 2 are the forward coils of nine .relays 11 to 19 lIlClllSlWB and both coils of speed of transmission adopted. The series1r90 circuit above referred to is then connected to tongue 4 of the line relay as through conductor 24. I

Each of the relays 11 to 19 inclusive has two tongues 25-26, 2728,- 29-30, 3132, 33-34, 35-36, 37-38, s9 40 and 41 12 respectively and a separate pair of stationary forward and back stop contacts for each tongue- A simple form of one of these relays is shown in greater detail in Fig. 5. i

The forward and back stationary contacts of the tongues 25, 27, 29, 31, 33, 35, 37, 39

and 41 form'the terminals of nine normal breaks in a shunt comprising wire 43 to which all of the back contacts of the said tongues are permanently connected and a wire 44: to which the forward contacts of said tongues are permanently connected the said wires being tapped on to the series circuit of the forward coils of .relays 1119 at points 45 and 46.

The tongues 25, 27, 29, 31, 33, 35, 37 39 and 41 of relays 11 to 19 are each tapped on to the series circuit of the forward coils of said relays at a point between its own forward coil and that of the next succeeding relay.

Resistances 47 are connected respectively in series between the forward coils of the several relays 1119 for the purpose-of preventing a transformer effect from taking placebetween the forward and back coils of these relays. With said resistances omitted, each forward coil would act as a short circuited secondary of a transformer withthe restoring or back coil of the relay T as the primary, and thus nullify the effect of the restoring impulse. These resistances in the apparatus used. are 500 ohms each..

48 to 55 inclusive represent eight selecting relays each of which has a single tongue and two stationary tongue contacts. These may be polar relays of usual or any desired construction. One terminal of the forward coils of alternate relays 48'-"55 are tapped on to conductors 56 and 57 respectively and these conductors are connected respectively to the forward contacts 58 and 59. of slow acting relays 20 and 21. The other terminals of the forward coils of relays 48 to 54 inclusive are connected respectively to the back contacts of relay tongues 28, 30, 32, 34, 36, 38 and 40, while the corresponding ter- 'minal of forward coil of relay is connected to the forward contact of relay tongue 40. Forward contact of tongue 26 is permanently connected to tongue 28; forward contact oftongue 28, connected to tongue 30, and so on to and inclusive of tongue 40. Tongue 42 and its forward contact form the terminals of a normal break in a local circuit inbluding an electro-magnet 60, which may be employed to operate a contact device for completing the restoring circuit of all of said relays. This contact device comprises in the case shown a clutch comprising a normally idle member 66' made fast to said sleeve and a normally rotating member-67 made fast to the shaft 65 the two said members being coupled together at times by spring actuated latch pin 68 when released by arm 69. The arm 69 is operated by magnet 60 as shown. This clutch simply indicates one of many ways of operating the circuit closing contacts of the restoring circuit.

Connected'in series with the forward contact of relay 21 are the coils of a relay 70,

which is adapted at times to short circuit,

brushes 63 of the restoring contact. The function of this relay as well as its construction will be fully described later.

The selecting relays 48 to 55 may be made to operate any desired receiving mechanism, such for example, as a printing telegraph receiver or the like, or, in fact, any desired apparatus which may be operated by the operation of local circuits selectively.

In the diagram Fig. 1, I have shown as indicating a form of receiving apparatus eight magnets 717 8 connected respectively to circuits controlled by the tongues of the selecting relays. These magnets may be the eight printer operating magnets of my application for Letters Patent of the United States for telegraphy filed June 17, 1910, Ser. No. 502,785 Patent No. 1,105,920, granted Aug. 4, 1914, or they may represent any other desired translating devices.

Telegraph receivers operated by a plurality of magnets energized selectively in combinations are well known in the art, and I do not herein claim any ofthese mechanisms as a part of this invention.

If applied to a system wherein the re corders are'synchronously driven, the selecting relays 4855 may, for example, be those of the Rowland system as described in U. S. Patent No. 713,497 granted November 11, 1902 or they may 'be the selecting relays of the automatic telegraph forming the subjectof U. S. Patent No. 942,844, granted December 7, 1909 on-anapplication filed by me.

The magnet 60 may be the printer spacing magnet of my application above referred to or may be used to start into operation any devices controlled by magnets 7 17 8, or for any other desired purpose.

The specific form of receiving apparatus herein shown and above described is particularly adapted to operate with signals which consist each of a group of electrical impulses alternating in polarity and in which certain of the said impulses are lengthened. Such a signal is shown in the diagram Fig. 19 where the line A-B represents the signaling current sent to line without modification to represent any particular slgnal, and line C-D, the said signaling current with two of its impulses lengthened.

According to a code of combinations which I have devised and which we shall assume for the purpose of illustration is the one used with the present apparatus, the signal, line C'D, represents the letter H. Another signal, the letter A, for example, is

1 ,is-amo formed by lengthening a combination of certain other impulses, while some other signal' may be formed by lengthening only a single impulse in the group.

The system of code combinations above referred to may be readily understood from the diagram Fig. 17, Where the horizontal row of characters and other signals along the upper edge of the diagram represent the various transmittible signals, the eight dots on alternate sides of the broken line w-y, the eight alternating impulses of a signal group, and the dots under each of the signals along the said horizontal row, the respective combinations in which the said impulses are modified to form the said signals. At the end of each signal a direct current is sent over the line to restore the receiving apparatus to its normal condition ready for a fresh signal. Assuming thatthis restoring current has been sent to line, the tongues of the various local receiving relays occupy the positions shown. In such a case current would pass from the positive terminal of a local source through resistance 10, contact 6, tongue 3 of. line relay 2, wire joint 16, forward coil and tongue 25 of relay 11, back contact of that relay, wire 43, coils of relays 20 and 21, inductance 22, wire 24 line relaytongue 4, contact 8, to negative return.

The forward coils of all the relays 12 to 19 inclusive are thus shunted or short circuited by a circuit including tongue 25, its back contact and wire 43. As the current reverses between the line and first or line and a impulses of the signal groupthe tongues of the line" relay 2 will be sent to contacts 5 and 7. This reverses the direction of the local current in the shunt circuit above traced causing relay ll'to send its tongues against their forward stops. This causes relay tongue 25 to short circuit its own forward coil, and this allows local current to traverse the forward coil of the next succeeding relay 12, but in such a direction as not to cause thatrelay to moveits tongue 27 from its back contact. This relay 12 then completes the shui1t around all the successive relays 13 to 19, and so on for each reversal of the signaling current. In this way, for each reversal of the signaling current one of the relays 11 to 19 short circuits its own forward coil While the next succeeding relay has its forward coil in circuit to be operated by the next reversal, but completes a shunt around the forward coils ofall the only, while relay 21 sends its tongue to its forward contact only when traversed by a positive impulse. Obviously by reversing the windings on these relays they may be made to operate on the reverse of the polarities above mentioned.

Let it be assumed that the signal H is received. This signal, as above pointed out, is formed by lengthening the b and e impulses of the group. When the current reversed between the a and b impulses, the tongue of relay 12 was sent to its forward contact thus cutting in the relay 13 and shunting relays 1a to 19. At the same time, tongue 28 of relay 12 is sent to its forward contact. Tongue 26 of relay 11 had, by the previous reversal, been sent to its forward contact. The Z) impulse being lengthened and positive will cause relay 21 to send its tongue to its forward contact. This completes a local circuit through the forward coil of selecting relay 49 which may be traced as follows: positive terminal of a local current source, tongue and contact 59 of relay 21, wire 57, forward coil of relay 49, back contact and tongue 30, forward contact and tongue 28, forward contact and I tongue 26, to negative of said local source of current. This causes tongue of relay 49 to close a local circuit in which magnet 7 2 is connected which may be traced as follows: from the positive terminal 81 leading from said local source of direct current, magnet 72, tongue of relay 19, wire 82, to negative of said local current. Each succeeding reversal of the line current will cause corresponding relays 141 9to send their tongues against their forward stops and in doing'so each of said relays cuts itself out of circuit, that is, its forward coil, and cuts the next succeeding relay in circuit. In other words, each successive relay short circuits its own coil and nullifies the short circuit around the next succeeding relay. The relays previously cut out in a similar way remain so until a general restoring impulse returns all the relays 1119 and 48 to 55 to normal.

But the relays 20 and 21, it must be remembered, operate only on lengthened impulses. The next lengthened impulse in the H signal is the e impulse (see Fig. 19). Therefore when this impulse operates the line relay an elongated local impulse corresponding thereto will traverse relays 20 and 21, and, as this impulse is negative, will operate relay 20, and the reversal of the current between the d and e impulses caused relay 15 to send its tongues against their forward contacts. The effect of these operations is to close a local circuit through the forward coil of relay 52, which circuit may be traced as follows: positive terminal 80, tongue and forward contact of relay 20, wire 56, forward coil of relay 52, tongue 36, and tongues 34, 32, 30, 28 and 26 which are all then against their forward stops, to negative return. This causes relay 52 to close the local circuit in which magnet 75 is connected.

When the tongue 42 of the last relay 19 of the series 1119 is'sent over to its forward contact by the h reversal of the line current, this completes a local circuit in which are connected the coils of magnet 60. This magnet then releases latch 69 from pin 68 which allows this pin to engage the normally rotating clutch member 67' and this sets in rotation disk 61 carrying contact 62, so that shortly after said disk starts to rotate, contact 62 engages brushes 63 and thereby completes a restoring circuit which may be traced as follows: from positive terminal 83 of a source of local direct cur rent, through the back coils of relays 1119 and 4855, wire 84, brushes 63 to negative return '85. Current in this circuit restores the tongues of all of said relays to their back stops ready to receive a fresh signal. In a similar way any of the signals in the diagram Fig. 14 may be received. The words Space, Line, Back and Blank indicate signals used in transmission to a page telegraph receiver which forms the subject of a separate application. In the operation thus far described it has been assumed that the impulses coming over the line do not get out of step with the relays 1119 and thus cause the wrong relays to act. To prevent this or to correct it if it should happen, is the function of slow acting relay 70, which, if its tongue is thrown to its forward contact will complete the restoring circuit through all the relays 1119 and 4855 and return these relays to normal. This relay 70 acts much more slowly than relays 20 and 21 and will not operate on the ordinary lengthened signal impulses. Should, however, an operator hesitate for a fraction of a second between two letters, assuming that the signals are sent from a manually operated keyboard,'t he relay 70 will operate and insure the starting of the next character or signal properly. As the. operator must necessarily hesitate at the end of every line, in operating a pa e printing system, the receiving device will, always be started correctly on everyv line at least. The relay 70 may be made, slow acting in a number of ways, but I have devised a special form of relay for this purpose which is very satisfactory. This relay is shown in detail in Figs. 2,3 and 4 and consists, among other parts of a suitable frame 86 in which are mounted the magnet coils 87, 88 on suitable cores, an armature or tongue 89 pivoted as at 90 and adapted at its lower end to contact at-times with screw 91 which forms the forward contact of the relay. The lower end of tongue 89 is engaged by the noseof a pivoted dog 92 which is forced against said armature under tension of spring 93. This dog has an arm 94 which is connected loosely to a rod 95 which carries at its upper end a cone shaped valve 96 which is adapted to seat on the head 97 of a hollow piston 98 open at its lower end and slidable by a close fit in a cylinder 99 closed tight at its upper end cured to the relay frame 86. The valve 96 controls an opening 100 through the head of piston 98. The arm 94 passes through an opening 101 in an extension 102 in the lower end of cylinder 99. The operation of this relay is as follows: When there is no current in coils. 87 and 88 the head of piston 98 rests upon valve 96 and the latter closes the opening 100, the armature 89 being drawn away from pole piece 103 by spring .93. When the coils 87 and 88 receive current, pole piece 103 attracts the upper end of armature 89, forcing arm 94 up. This will force rod 95 up and with it the piston 98. Since at this time valve 96 is closing opening 100, and since the piston 98 makes an air tight fit in the cylinder 99 there will be a cushioning effect in the space aheadv of the piston head 97 which will greatly retard this upward movement, producing a dash pot effect. The lower or contact end of armature 89 will therefore approach contact screw 91 very slowly. When, however, current ceases in coils 87 and 88, spring 93 draws the outer end of dog 92 quickly up thereby forcing down arm 94 and with it rod 95 and valve 96. This removes valve 96 temporarily from opening 100, allowing the piston 98 to return quickly to its normal position. It is necessary that the parts of this relay return quickly to their normal positions, otherwise the relay would not fully return after a long impulse, 1Il Wl11Cl1 case a short impulse might be sufiicient to throw its tongue against contact 91.

'By adjusting the amount of motion and tightness of piston 98 in cylinder 99, the relay may be made to operate with various degrees of slowness as desired. It should operate only on impulses several tlmes as long as the impulses used for the signal combinations, so that there shall be ample operating margin.

Any suitable transmitting apparatus may be used for forming the signals. That here shown comprises among other parts (see Figs. 6 to 16) a shaft 104 1ournaled 1n suitable bearings 105, 106 and constantly driven from any suitable source. This shaft carries, among other parts, a ratchet 107 fast thereon and a clutch member 108 free to rotate on said shaft but held against longitudinal movement. This clutch member 108 is provided with two annular flanges 109 and 110 in which are mounted for movement transversely thereof two latches 111 and 112. These latches are provided reand open at its lower end and rigidly se- 119. all rigidly secured together.

the rings 118 carries a small cam 120 spaced- 107. The nose 113, however, is longer than dinal movement a sleeve 117 which is made,

up of a plurality of rings 118 and a collar apart spirally around the sleeve 117. This sleeve while being slidable longitudinally on the sleeve 116 is held against rotation relative thereto by a slot andfeather or other well known or suitable connection.

The collar 119 has a flange 121 which is adapted to be engaged by the latches 111 and 112 in the following manner: Latch 111 has an extension 122 with a slot 123' in it. into which the flange 121 fits with little or no lost motion longitudinally of the latch; while latch 112 has an extension 124 with a wider slot 125 therein which the flange 121 engages, but which allows a certain amount of longitudinal movement of the pin in one direction relative to the said flange.

Latch 112 is cut away asat 126 to form a recess to receive a pin 127, one of the side walls of said recess having a cam surface 128 adapted as hereinafter described to engage said pin to disconnect said latch from said ratchet and to stop the rotation of clutch member 108. Also mounted fast on sleeve 116 are three cams 129, 130 and 131, and between these cams and the lower end of sleeve 117 is a'coil spring 132 which normally forces sleeve 117 up so that collar 119 engages a shoulder on sleeve 116. lams 129 and 130 have each five equally spaced projections and these two cams are so staggered relative to each other that the projections of one lie opposite the depressions of the other so that there are ten equally spaced projections in the circle. (See Fig. 8).

Cams 129 and 130 operate respectively two pivoted arms 133 and 134 which in turn operate respectively two contact springs 135 and 136 mounted upon suitable insulating;

supports 137 and 138, in line with two contact screws 139 and 140 which may be mounted on any suitable support, preferably a metal bridge. since these screws are permanently electrically connected together.

The contact springs 135 and 136 are electrically connected respectively to the positive and negative terminals of any desired source of direct current which, in the accompanying drawing, is represented as being two direct current dynamos 141 and 142 connected to earth and to the springs 135 and 136 as shown.

The main line is indicated by wire 143 Each of I connected to both contact screws 139 and 140.

The cams 120 are spaced around the sleeve 117 so that one shall lie opposite or in line with each of the projections of cams 129 and 130, there being ten cams 120 and ten projections in'-thev combined cams 129 and 130. Cains 120 are adapted to engage at times with cams 144.0n eight levers 145 mounted on a common fulcrum 146 and normally held bv individual springs 147, so that cams 1 1-l will be out of the paths of cams 120. The cam heads of levers 145 work in slots 148 in stationary block 149 so as to hold said levers against the side strain which their heads are subjected to in engaging cams 120. (See Fig. 7).

All the stationary parts thus far described may be mounted on a supporting plate 150 in any suitable manner. The mounting of many parts has been omitted from the drawing for the sake of clearness.

F or the purpose of operating the levers 145 I provide eight pins 151, one individual to and in line with each of said levers, mounted in two rows of four pins each and staggered as shown most clearlyin Fig. 7. These pins are mounted for longitudinal movement in the plate 150, and may be operated either automatically or manually. In the machine shown they are operated by a series of selector bars 152 which are in turn operated by key levers 153 of a manual keyboard. There is a selector bar 152 individual to each pin and each selector bar is provided with an extension 154 adapted to engage its pin. These selector bars are mounted for longitudinal movement on rods 155 (one only shown) which pass each through slots 156 in said bars, and for the purpose of operating these bars from the said key levers to give such movement to thenneach bar carries on its lower edge a number of cam lugs 157 which are adapted to be engaged by the cam edges 158 of the key levers and thereby shifted longitudinally. By arranging these lugs on said bars so as to be engaged in certain combinations by the several keys, the said bars are caused to operate said pins in these combinations. The manner of arranging these lugs on the selecting bars will be clear from a study of Fig. 18 which shows in side elevation four of the bars removed from the machine. These lugs are simply arranged so that there will be the required number in line with each key lever to shift that one Therefore, the a and 03 bars 152 would each have a lug adapted to be engaged by the beveled edge of the A key lever, so that when the A key 'is operated the said a and 11 bars will be shifted.

Each selector bar carries on its upper edge a lug 159 any one of which is adapted, when its bar is operated, to engage a yoke 160 which spans all the selector bars and is faston one end of a pin 161flongitudinally slida-ble in plate 150. The end of this pin 161 opposite the yoke 160 is adapted to engage the arm of a dog162 mounted upon a common fulcrum 163 with a lever 164, but movable relative to said lever.

Pivoted on one arm of lever 164 is a pawl 165 one arm of which is adapted to engage a shoulder 166 on the dog 162, and another arm of said pawl is adapted to be engaged at times bya cam lug 167 on flan e 109 of the clutch. (See Figs. 12 and 13 The lever 164 carries the clutch pin 127 which is normally forced forward into the recess between flanges 109 and 110 byspring 168. The arm of dog 162 is pulled in the direction of pin 161 by spring 169, and the pawl 165 in under tension of spring 170 as shown.

The key levers shown indicate but two of a keyboard which may have as many keys as I ing each signal, that is, after a given key is operated, this and the other keys are locked until the signal is sent. This is effected in the present case by providing each key lever with a lip 171 (see Fig. 16) which is adapted to be engaged at times by alocking bar 172 which extends across all the key levers and is mounted at each end upon suitable pivoted uprights 173. The keys are locked and unlocked by reciprocating said bar, and this is effected in the present machine by a bell crank lever 174 one arm ofwhich engages upright 173 and the other, the cam 131.

The operation of the foregoing transmitting apparatus is as follows: Shaft 104'1'0- tates continuously. Consider first the normal condition of the line when no signals are being sent, but with the shaft 104 rotating and the apparatus ready for operation.

7 During this time all the keys of the keyboard are unlocked, since cam 131 always comes to rest in that position where its lug engages the lever 174 thus forcing locking bar 172 out of engagement with the key levers. Also during this time arm 133 forces spring 135 into engagement with contact screw 139, while arm 134 rests in one of the recesses of cam 130 and allows spring 136 to break contact with screw 140. The cams 129 and 130 always come to rest so as to leave the arms 13 3 and 134 in these positions. The result of this is that during'this time the line 143 receives positive current .con

tinuously from dynamo 141, through contact 135 and 139. Also during this time of no signal, nose 127 is in engagement with latch 112 forcing it against tension of spring 112 downward so that its nose 114 is out of the path of the teeth of ratchet 107, in which position its lip 124 does not engage flange 121. Also cam sleeve 117 is forced up to the position shown most clearly in Fig. 11, so that latch 111 does not engage ratchet 107. This allows said ratchet to rotate freely with shaft 104 out of engagement with either of the clutch latches. Next, suppose a key of the keyboard is operated, and let it be assumed that this is the key corresponding to the letter H. The operation of this key will cause its cam edge to engage lugs 157 of two of the selecting bars 152 thus pushing these bars to the right, Fig. 6. The operation of these bars will force pin 161 to the right and this in turn engaging dog 162 will impart angular movement to said dog, and since shoulder 166 is now engaging pawl 165, angular movement will be imparted to the clutch pin lever 164 causing it to withdraw its nose or pin 127 from engagement with latch 112, which being thus released will be forced under pressure of spring 112 upward, so that its nose 114 will engage one of the teeth of ratchet 107. This couples sleeve 116 to shaft 104 which causes the latter .to rotate and with it the cam sleeve 117, and cams 129, 130 and 131. Directly after sleeve 116 commences to rotate, the lug of cam 131 leaves lever 174 thus causing it to rock locking bar 172 forward into engagement with the lips 171 of all the key levers, thus looking all the keys against operation until the complete signal is sent. The rotation of cams 129 and 130 oscillates arms 133 and 134 causing them to bring contact springs 135 and 136 alternately into engagement with their respective stationary contacts 139 and 140 thus sending from dynamos 141 and 142 to line current impulses alternating in polarity. As there are ten cam projections on the combined cams 129 and 130, ten such impulses will be sent to line for each signal with this apparatus. This current as modified for a signal is indicated at 'AB Fig. 19. I

Whenthe H key'was operated this operated the b and e selector bars, according to the code' herein assumed, and these bars in turn operated corresponding pins 151 which, engaging corresponding levers 145 force the cam ends 144 of these two levers into the paths of corresponding cams 120 on sleeve 117.

When the cam 120 corresponding to the b lever 145 engages the cam 144 of that lever the sleeve 117 is forced downward against tension of spring 132. This draws the nose 113 of clutch latch 111 into the path of the teeth of ratchet 107 and will disengage nose of latch 112 from said ratchet. This allows maaeao the sleeve 116 carrying cams 129 and 130 to lag back the distance .of half a tooth of ratchet 107, the nose 113 of the clutch latch being suiiiciently narrow to allow this lost motion. Sleeve 117 continuing its rotation will thentake the cam 120 in engagement with the b lever 145 past that lever, which will allow spring 132 to force sleeve 117 up again, disengaging nose of latch 11 from ratchet 107, and bringing nose of latch 112 into the path of ratchet 107. The ratchet ten in number corresponding to the total cam projections on the combined cams 129 and 130. The result therefore of this lost motion of the sleeve 116 is to cause a corresponding lost motion of the cams 129 and 130, and the effect of this in turn is to cause the levers 135 and 136 to remain for a prolonged period against their line contacts thereby lengthening the impulses which pass through them to line. Therefore when the b lever 1455 operates cam sleeve 116, we have prolonged b impulse on the line. Likewise when the e lever 145 is operated we get a prolonged e impulse on the line, as shown at CD, Fig. 19.

In a similar Way any of the other signals may be sent, the clutch and cam carrying sleeve 116 making one revolution for each signal, at the end of which cam 131 stops in that position shown in Fig. 6 to unlock all the keys, and the arm 133 in that position to send positive current to line.

Obviously if desired the cams 129 and 130 could be shifted so as to send negative current to line at the end of each signal in stead of positive.

Tn transmitting a Word it will be seen that the successive letters of this word are sent respectively in the times of successive revolutions of sleeve 116. In order, therefore, to return pin 127 to a position to operate the clutch latch112 for the next succeeding letter, means are provided for accomplishing this result. This is efiected by the pawl and dog mechanism of the clutch lever 164, the operation ofwhich is as follows When pin 161 moves forward under the action of the operated selector bars, it causes dog 161- to turn on its pivot, and this acting through shoulder 166 in engagement with.

pawl 165 rotates lever 16%, causing it to withdraw its nose 127 from the clutch latch and allow the coupling of the clutch as described. Shortly after the clutch has thus become coupled, by which rotation is imparted to its normally stationary member 108, cam lug 167 on said member engages the pawl 165, throwing it out of engagement with shoulder 166 of dog 162, thereby releasing arm l6etwhich, under tension of spring 168 sends its nose 127 into position to engage clutch pin 112 when it comes around to said nose. In Fig. 12 this mechanism is shown in the normal stopping position, while in Fig. 13, its parts are shown in the positions they occupy just after cam 167 has released pawl 165 from shoulder 166.

At the end of a signal and after the keys have been unlocked pin 161 returns to normal under tension of spring 169 which rotates dog 162 until shoulder 166 engages pawl 165. The parts will then be in the stopping position of Fig. 12.

The transmitting apparatus per 86 here shown is not claimed in this application. Claims covering said apparatus are embodied in my co-pending application Serial No. 768,773.

Having thus described a specific embodiment of my said invention, ll wish it to be understood that this is susceptible to many modifications without departing from the spirit thereof. Again, While it have described my invention as applied to simplex operation it may be worked duplex or multiplex by Well known methods, or such as it may devise.

What I claim is 1. Selective signaling apparatus comprising, in combination, means to send groups of signal impulses over a line, receiving relays responsive to all the impulses in each signal group, a series of auxiliary switches operated by said relays, receiving means responsive only to selected impulses of said groups, and a series of local circuits each of which is controlled by the conjoint action of .one of said first relays and auxiliary switches with said receiving means.

2. Selective signaling apparatus, comprising, in combination, means to send groups of signal impulses over a line, of receiving relays responsive to all the impulses in each signal group, and slow acting receiving relays responsive only to selected prolonged impulses of said groups, a series of local circuits each of which is controlled by the conjoint action of said first relays with said local circuits each of which is controlled by the conjoint action of said first named local relays and said second named local relays,

and a selecting relay operated by each of tacts in each of said circuits, electrical contacts common respectively to separate sets of said circuits, means responsive to a plurality of received electrical impulses for each signal to operate all of the-first mentioned contacts to partially close the operating circuits of all of said magnets, and means responsive to a givenone or combination of received selected electrical impulses only, and adapted thereby to complete the operating circuit of thoseonly of said magnets which correspond to that one or combination of signaling impulses se lected.

5. Selective signaling apparatus, comprising a plurality of selecting relays, a plurality of local circuits each of which includes amagnet coil of one of saidselecting relays, electrical contacts in each of said circuits, electrical contacts connected respectively in alternate ones of said circuits, means responsive to a plurality of received electrical impulses for each signal to operate all of the first mentioned contacts to partially close the operating circuits of all of said selecting relays, and means responsive to a given oneor combination of received electrical impulses and adapted thereby to complete the operating circuit of those only of said selecting relays which correspond to that one or combination of signaling impulses selected.

6. In a selective signaling system, the

- combination with a line signaling circuit,

of a main line receiver included in and operated by current 1n said circuit, a local circuit, means whereby the operation of said receiver sends a plurality of electrical impulses over said local circuit for each signal, a plurality of local relays the forward coils of which are connected in series in said local circuit, each of said relays except the first of the series bein normally short I circuited, electrical connections whereby the operation of said relays by said impulses causes each of said relays successively to short circuit its own coil and nullify the short circuit around the forward coil of the next succeeding relay, a plurality of local circuits, means responsive to one or more selected impulses only of those operating the foregoing local relays and adapted to cooperate with the latter relays to operate said last named local circuits, translating devices connected in said local circuits, and

means to impress a series of electrical impulses on said line for each signal whereby 5 said line relay is caused to vibrate its tongue.

7. A selective signaling system comprising means to transmit a plurality of electrical impulses and modify one or more of these for each signal, a plurality of series connected relays certain of which are responsive to all theimpulses for each signal and certain others of which are responsive only to selected modified impulses of said signal, a variable shunt connected around the series connected relays responsive to all said impulses, taps including the tongues of said last named relays connected to points in the series connection, of said relays at points between the respective relays, whereby the relays responsive to all the impulses are in circuit intermittently and the other relays in circuit continuously.

8. A selective-signaling system comprising means to transmit a plurality of electrical impulses and modify one or more of these for each signal, a plurality of series connected relays certain of which are responsive to all the impulses for each signal and slow acting relays responsive only to selected modified impulses of said signal, a variable shunt connected around the series connected relays responsive to all said impulses, taps including the tongues of said last named relays connected to points in the series connection of said relays at points between the respective relays, whereby the relays responsive to all the impulses are in circuit intermittently and the slowgacting relays in circuit continuously.

9. A selective signaling system comprising means to transmit a plurality of electrical impulses and modify one or more of these for each signal, a group of relays responsive to all the impulses of each signal, and other relays responsive only to selected modified impulses of said signals, electrical connections and means whereby the relays responsive to all the impulses are in circuit intermittently, and the other relays responsive to selected impulses in circuit continuously, and a plurality of local circuits controlled by the conjoint action of said two 4 sets of relays.

to all of the impulses of each group, and

other translating devices also in said local circuit but responsive only to selected impulses of said group, and a plurality of local circuits controlled by the conjoint action of said two sets of translating devices.

ll. Selective electrical signaling apparatus comprising a plurality of electrical contacts, conducting means adapted to engage said contacts alternately, a plurality of switches, each operated by individual electrical means, means whereby the alternate engagement of said conductor with its said contacts operatessaid switches in successive step-by-step order, a series of auxiliary' switches operated in corresponding step-by-step order by said electrically operated switching devices, and a series of electrically operated translating devices con- 15 trolled by said auxiliary switches.

lln testimony whereof ll aifix my signature in presence of two witnesses.

LOUIS MAXWELL POTTS. Witnesses: 1

FRANoIs S. MAGUIRE, JOHN H. HOLT. 

